1. Field of the Invention
The present invention according to one embodiment relates to an audio apparatus in which audio data stored in various databases are listed on a folder-to-folder basis, clearly based on the presence of a file in each folder.
2. Description of the Related Art
One widely-used method for clearly listing many files stored in a database is to include the same type of files in a folder and include the same type of folders in an upper-level folder. In this method, a file stored in the database can be used by selecting a folder sequentially from the top-level to lower levels and finally finding a desired file. The folder structure of such a database organizes files currently stored in the database, and can additionally create a folder in advance for a new category expected to be stored in the database so that, when data in the new category is input, the data can be quickly included in that folder that can be quickly available.
FIG. 5 shows an example of the above-described folder structure. FIG. 5 illustrates a hierarchical structure of folders in which files of various tunes are stored in mp3 or wma format in a database in a memory, hard-disk or the like in an audio apparatus. In FIG. 5, a “ROOT” exists as the top-level folder, and “AAA.mp3” and “BBB.mp3” files exist in the “ROOT” itself, or directly under the “ROOT.”
A “Folder A” and a “Folder B” exist as lower folders belonging to the “ROOT,” or as folders under the “ROOT.” Directly under the “Folder A,” a document file “WARD.doc” exists, and no tune file that can be played by the audio apparatus (referred to as playable file) exists. On the other hand, a “Folder C” and a “Folder E” exist under the “Folder B.” No tune exists directly under the “Folder C.” “FFF.mp3” and “GGG.mp3” tunes exist directly under the “Folder E.”
Although no tune exists directly under the “Folder C”, a “Folder D” exists under the “Folder C,” and three tunes exist directly under the “Folder D,” which include “CCC.mp3” and “DDD.mp3” tunes (audio files in mp3 format) and an “EEE.wma” tune (audio file in wma format). Further, the two tunes exist directly under the “Folder E” as described above. A “Folder F” and a “Folder G” exist under the “Folder E.” No tune exists directly under the “Folder F”, but “HHH.mp3” and “III.mp3” tunes exist directly under the “Folder G.”
When the database in which these tune data are stored with the folder structure shown in FIG. 5 resides in a car audio apparatus, the display area is too limited to list the folder structure in detail. For example, in reality, the folders would be listed entirely in parallel without any hierarchical structure, as shown in FIG. 6(a). In the example shown in FIG. 6(a), the display of a car audio apparatus capable of listing six folders lists all folders, such as “ROOT,” “Folder A,” . . . “Folder E,” without any hierarchical structure. In this example, the numbers of tunes included in the folders are shown as 2, 0, 0, 0, 3, 2 from top to bottom.
The car audio apparatus, when used by a driver, needs to perform the listing understandable at a glance in such a small display area in order not to interfere with driving. Thus, the listing would inevitably be a parallel listing as shown in FIG. 6(a). However, in order to list the folders anyway with their hierarchical structure, the folders may be listed indented based on the structure in FIG. 5, for example as shown in FIG. 6(b). In addition, in order to further highlight the hierarchical structure, a tree structure indicating the hierarchical structure may be additionally displayed as shown in FIG. 6(b). This method is well known as a hierarchical listing of folders in personal computers.
JP-A-2004-030116 discloses a method for listing folders in different hierarchical levels in a storage medium aligned with each other regardless of their hierarchical levels, according to a playlist management table. JP-A-2007-250036 discloses a method for displaying structure information by analyzing hierarchical structure of folders stored in a storage medium, creating the structure information including information on the hierarchical structure and information on data stored in the folders, and marking a folder that does not include available data as empty folder.
As described above, when listing folders included in a database on a small display area such as the display of a car audio apparatus as shown in FIG. 6 in a manner understandable at a glance to drivers, a method of not displaying the hierarchical structure of the folders, as shown in FIG. 6(a), is often used. Further, the hierarchical structure of the folders may be displayed according to a method used by conventional personal computers, as shown in FIG. 6(b).
However, according to this displaying method, since the entire hierarchical structure of the folders is simply displayed as it is, even a folder directly under which no file (tune) exists is displayed. In the example shown in FIG. 6(b), although no tune exists directly under the “Folder A” and any folder under the “Folder A,” the “Folder A” is always displayed. It would be extremely undesirable for a user searching for a desired tune to be always displayed such a meaningless folder, especially on an apparatus with a small display area. This case is not shown in FIG. 6(b), but as seen from FIG. 5, the “Folder F” is always displayed by scrolling FIG. 6(b).
Further, in the example shown in FIG. 6(b), no tune exists directly under the “Folder B” and the “Folder F.” Focusing the “Folder B,” tunes only exist directly under the “Folder D” under the “Folder C” under the “Folder B” and directly under the “Folder E” under the “Folder B.”
In the case that no tune exists directly under one folder and a tune exists directly under another folder under the one folder as above, displaying the hierarchical structure of the folders is useful for a user to understand it. However, for example, when using the database on a car audio apparatus, the user's first priority is to search for a desired tune, and the user does not necessarily need to know the hierarchical structure of the folder directly under which the tune exists. However, the user is more likely to know the hierarchical structure than in the case that no file exists directly under one folder and any folder under the one folder.
Accordingly, it is desirable that the hierarchical structure of the folder directly under which the tune exists can be displayed on the display, and, when the user absolutely needs to know the hierarchical structure, the car audio apparatus, for example, displays the hierarchical structure in a manner understandable if the user stops the car and observes thoroughly. Such a need also exists not only in a car audio apparatus but also in a home audio apparatus, and a similar need exists in using an apparatus with a small display area, such as personal digital assistant or mobile phone, as audio apparatus.
In view of the above, it is an object of the present invention according to one embodiment to provide an audio apparatus in which, when many files stored in a database are organized in folders, the folders can be listed in a manner understandable at a glance even on a small display area and with a hierarchical structure in the minimum level of detail.